Last week several hundred lawyers blocked the road outside the MoJ in central London in protest against legal aid cuts. Photograph: Christian Sinibaldi for the Guardian

Court staff are being called out on strike on Monday amid growing opposition to the Ministry of Justice's proposals to contract out services, cut legal aid and limit the use of judicial review.

The threat of courtroom disruption comes as the government's own watchdog, the Equality and Human Rights Commission (EHRC), warned on Thursday that the plans "may have an adverse impact on the right to a fair trial" and "exclude vulnerable people from access to justice".

How effective the industrial action will be is uncertain. In Manchester, lawyers will join members of the Public and Commercial Services union (PCS) who work in the courts and crown prosecution service for a lunchtime demonstration.

Last week several hundred lawyers blocked the road outside the MoJ in central London in protest against legal aid cuts. The PCS has already begun a series of rolling actions which have so far had a relatively limited effect, but the strikes planned for next Monday are more widespread.

Mark Serwotka, the PCS general secretary, said: "These workers provide vital services every day across our justice system, and they do not deserve to be shunned by ministers who are refusing to even talk to us about the cuts they are imposing."

John Nicholson, a Manchester barrister who specialises in immigration cases and is coordinating the demonstration, told The Guardian: "This is the first time lawyers and court staff have joined together. We are defending access to justice and legal aid; we are against privatisation."

In its submission to the MoJ's consultation, the EHRC, the government's statutory on equality and human rights issues, says: "The proposed changes could have an adverse impact on access to justice which would be incompatible with equality law [and]... on the right to a fair trial under Article 6 of the European Convention on Human Rights. These impacts may be accentuated for more vulnerable or disadvantaged individuals."

The commission urges the government to withdraw its plans to reduce funding for judicial reviews and impose tighter time limits. "Applications for judicial review act as an effective check on the exercise of power by public authorities, protecting the rule of law and allowing individuals to obtain redress," it says. "Judicial review is sometimes the only means of appeal from an administrative decision or from an internal complaints procedure..."

It warns that the residence test proposed would deny migrant children as well as recently arrived victims of domestic violence and trafficking legal representation. Mark Hammond, chief executive of the EHRC, said: "The right to go to court as a last resort, and the right to have a fair trial and a decent standard of legal representation are important protections for us all and we should ensure they are available to the most disadvantaged."

The Justice Secretary, Chris Grayling, will appear before the the Commons' justice select committee on 3 July to answer questions about his legal aid consultation.

A Ministry of Justice spokesperson said: "At £2bn a year we have one of the most expensive legal aid systems in the world and must ensure we get best value for every penny of taxpayers' money spent. We have just finished consulting on a number of proposals to reform legal aid and are now carefully examining all the responses. Quality, professional lawyers would still be available to anyone needing advice or charged with a crime just as they are now."